Dynamical Modeling and Characterization of Peak-Current-Controlled Superbuck Converter

The fourth-order converter known as superbuck is often used to interface the solar arrays into the rest of the power system due to the continuous input current it provides. Peak-current-mode (PCM) control is applied. The small-signal models of such a converter do not exist in public domain literature and its dynamical features are not known. The paper introduces the dynamical modeling based on consistent methods. The characterization shows that the PCM-controlled superbuck converter may have similar features characteristic to the conventional buck converter such as high input-voltage-noise attenuation, effectively first-order output dynamics, and high insensitivity to source interactions, when the inductor-current feedback is properly compensated. The converter is, however, more susceptible to the input-filter instability due the shape of the ideal input impedance than the conventional buck converter. Experimental evidence is provided based on a 440-kHz converter.